Noise damping means for electromagnet



' March 24, 1970 F. w. KUSSY- ET AL 3,503,019

NOISE DAMPING MEANS FOR ELECTROMAGNET Filed Oct. 26, 1967 4 Sheets-Sheet 1 L mi 45.

1N ENTOR I Fen/vz MXL/V55?? March 24, 1970 F. w. Kussv ET AL 3,503,019

NOISE DAMPING MEANS FOR ELECTROMAGNET v 4 sheets-sheet 2 Filed Oct. 26, 1967 INVENTORJ' F/PAAM/ al. ,kd

March 24, 1970 F. w. Kuss-Y ETAL 3,503,019

ANOISE DAMPING MEANS FOR ELECTROMAGNET Filed Oct. 26, 1967 4 Sheets-Sheet 5 INVENTORS Fei/VA ld. e1/55) March 24, 1970 F. w'. Kussv :TAL 3,503,019

NOISE DAMPING MENS FOR ELECTROMAGNET 4 Sheets-Shet 4 Filed Oct. 26, 1967 I a; .5.. W //f..

/f' NZ United States Patent O NOISE DAMPING MEANS FOR ELECTROMAGNET Frank W. Kussy, Birmingham, Andrew J. Kralik, Detroit, and Robert Schuster, Fraser, Mich., assignors, by mesne assignments, to I-T-E Imperial Corporation, Philadelphia, Pa.. a corporation of Delaware Filed Oct. 26, 1967, Ser. No. 678,237 Int. Cl. H01h 3/ 60 U.S. Cl. 335-193 10 Claims ABSTRACT F THE DISCLOSURE An electromagnetic contactor having a stationary laminated yoke and a movable armature is provided with a relatively shallow nylon pan which surrounds a portion of the yoke and is closely fitted thereto to damp transmission of vibrations from the yoke laminations to the base of the magnet thereby reducing noise attributable to vibration of the magnet. In addition, a cross-piece holds the magnet yoke on a single pivot point against the forces of the contact springs to permit full seating of the armatureyoke mating surfaces. A pad constructed of closed cell silicone sponge rubber is interposed between the armature and a movable portion of the 'base to absorb impact forces and damp vibration of the armature.

This invention relates to electromagnetic contactors in general and more particularly relates to means for reducing noise due to vibration of the yoke against the armature in an A.C. energized magnet.

As the size of A.C. energized contactors increases, the noise due to vibration of the magnet increases to the point wherein a size contactor (rated 200 H.P., 480-600 volts and 300 amps max.) the noise reaches objectionable lev els unless appropriate suppression methods are utilized. The situation can -be particularly bad when the base of the contactor is constructed of relatively rigid insulating material in that this noise is amplified when the yoke is fastened to the base and/or even touches the base or an element, such as a metal spring, which is not sound absorbing.

The instant invention improves the basic electromagnetic contactor structure of the I. B. Cataldo et al., U.S. Patent No. 3,324,431 issued June 6, 1967, for an electromagnetic contactor having interchangeable auxiliary devices by mounting the yoke in a shallow pan-like member constructed of non-cellular vibration damping plastic material such as nylon or other material having the noise absorbing properties thereof. The rim vof the pan-like member surrounds a portion of the yoke and is relatively close titting with respect thereto while the bottom of the pan is interposed between shock absorbing metal spring means and the stationary portion of the base.

A further improvement in overall contactor operation is achieved by utilizing a pad of closed cell silicone sponge rubber interposed between the armature and movable base as a shock and vibration absorbing means.

Accordingly, a primary object of the instant invention is to provide an improved construction for an electromagnet.

Another object is to provide an electromagnetic contactor having novel noise absorbing means.

Still another object is to provide a noise absorbing means of this type constructed of nylon.

A further object is to provide a noise absorbing means of this type which includes a pan-like portion wherein the yoke is disposed with the rim of the pan surrounding a portion of the yoke in close fitting relationship thereto.

A still further object is to provide an electromagnet in which the yoke is pivoted to allow full seating of the 3,503,019 Patented Mar. 24, 1970 ice' armature to the yoke, a nylon pan-like member or sleeve suppresses noise due to vibration of the yoke laminations, and a pad of closed cell sponge material interposed between the armature and movable base absorbs mechanical shock and damps vibration of the armature.

These as well as other objects of this invention shall become readily apparent after reading the following description of the accompanying drawings in which:

FIGURE l is a perspective of an electromagnetic contactor including novel features constituting the instant invention.

FIGURE 2 is an exploded perspective showing the main elements of FIGURE 1,

FIGURE 3 is a schematic showingthe basic connection between an electromagnet and the three sets of contacts operated thereby.

FIGURE 4 is a side elevation of the nylon pan-like member or sleeve for reducing noise generated by vibration of the laminations constituting the magnetic yoke.

FIGURES 4A and 4B are elevations of the member of FIGURE 4 looking in the directions of the respective arrows 4A, 4A and 4B, 4B.

FIGURE 5 is an exploded perspective of the magnetic frame members together with their associated shock a-bsorbing means, noise reducing means, and central pivot means.

FIGURE 6 is a side elevation showing the elements of FIGURE 3 in assembled relationship.

Now referring to the figures. Electromagnetic contactor 10 of FIGURE 1 is of the basic construction described in detail in the U.S. Patent No. 3,324,431 so that a detailed description of the entire contactor 10 will not be given herein. Briefly, contactor 10 includes main stationary base 11 constructed of phenolic or other rigid plastic secured to mounting plate 12 by means not shown. Auxiliary stationary base, or stationary contact carrier 13, is mounted on four posts 14 in spaced relationship with main stationary base 11. Also mounted on posts 14, in a Vposition between stationary base sections 11 and 13, is movable contact carrier 15 having portions which extend upwardly through apertures (not shown) in stationary contact carrier 13 and carry three movable bridging contacts 16a, 16h, 16C. Return springs 19 on each of the posts 14 bias movable contact carrier 15 against stationary contact carrier 13 to separate bridging contacts 16a, 16h, 16C, from their cooperating pairs of stationary contacts 17a, 18a; 17b, 18b; 17C, 18C, respectively.

Removable insulating cap 26 normally covers all three sets of cooperating contacts. In a manner Well known to the art the respective sets of cooperating contacts are closed simultaneously by an electromagnet consisting of double coil means 20, U-shaped stationary yoke 21 mounted to main base 11, and armature 22 mounted to movable contact carrier 15.

Yoke 21 is entered into shallow recess 11a of main stationary base 11 and is retained therein by plate 21a and screws 2lb. Similarly, armature 22 is maintained within shallow recess 15a by bracket 22a and screws 22b.

Yoke 21 is of U-shape, is constructed of'laminations and includes arms 31a, 31b joined together by connecting portion 31e and extending toward armature 22. Connecting portion 31e is entered into the shallow pan-like portion 34 of member 33 with the rim section 35 of the pan-like portion 34 surrounding and being snugly fitted to the section of connecting portion 31c most remote from armature 22. Two partially loaded leaf springs 36 bear against wall 11b of recess 11a yand the bottom wall 34a of pan-like portion 34 to bias yoke 21 toward armature 22.

Member 33 is constructed of non-cellular plastic material having the sound absorbing properties of nylon so 3 that member4 33 effectively reduces noise causedfby the vibration of the yoke-armature mating surface to an acceptable level. Projections 37a of member 33 extend from pan-like portion 34 toward armature 22 and contribute toward isola-ting vibrations of magnet 21, 22 from main base 11 regardless of the mounted position for contactor 10. It is noted that contactor is constructed to be mounted in any angular position so long as mounting plate 12 is in a vertical plane.

Sheet 41 within recess 15a is constructed of phenolic laminate and is interposed between armature 22 and movable contact carrier 15. Partially compressed pad 42 constructed of closed cell silicone sponge rubber is disposed within recess 15a and is interposed between sheet 41 and armature 22 as'a shock absorbing and damping means for armature 22.

Thus, this invention provides novel means in the form of a nylon sleeve surrounding the magnet yoke to isolate vibration of the magnet 21, 22 from the main base thereby reducing magnet noise.- A closed cell silicone sponge rubber pad interposed between the armature and movable contact carrier functions as a shock absorber and vibration damping means.

Although there has been described a preferred embodiment of this novel invention, many variations and modifications will now be apparent to those skilled in the art. Therefore, this invention is to be limited, not by the specific disclosure herein, but only by the appending claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. A contactor including cooperating contact means; an electronmagnet connected to said contact means for operation of said contact means from a normal position to an operated position; return spring means urging said contact means to said normal position; said electromagnet including a laminated relatively stationary yoke, a relatively movable armature, and coil means for generating magnetic flux for moving said armature toward said yoke; said return spring means urging said armature away from said yoke; a base including a stationary section, constructed of rigid plastic, and a movable section; means connecting said yoke to said stationary section, means connecting said armature to said movable section; first cushion means interposed between said yoke and said stationary section; second cushion means interposed between said armature and said movable section; and additional means interposed 'between said yoke and said stationa'ry section to isolate the latter from vibration of said yoke when said coil means is energized by A.C. current;

said additional means constructed of non-cellular vibration damping plastic material and surrounding a portion of said yoke in close fitting relationship therewith.

2. A contactor as set forth in claim 1 in which said plastic material is nylon.

3. A contactor as set forth in claim 1 in which said additional means includes a pan-like portion wherein said yoke is disposed.

I4. A contactor as set forth in claim 3 in which said yoke includes a plurality of tingers joined by a connecting portion; said armature confronting the free ends of said fingers, said connecting portion being disposed in said pan-like portion.

5. A contactor as set forth in claim 1 in which movement of said armature is generally horizontal and said return spring means acts horizontally.

6. A contactor as set forth in claim 5 in which said first cushion means comprises loaded metal spring means bearing against said stationary section and said additional means.

7. A contactor as set forth in claim 6 in which said plastic material is nylon.

8. A contactor as set forth in claim 7 in which said yoke includes a plurality of fingers joined by a connecting portion; said armature confronting the free ends of said fingers, said additional means including a pan-like portion wherein said connecting portion is disposed; said `pan-like portion including a bottom wall disposed in a References Cited UNITED STATES PATENTS 2,977,438 3/1961 MOrsChel.

3,046,456 7/1962 Petrus.

3,170,054 2/1965 Lawrence.

3,196,231 7/ 1965 Meyer.

3,243,545 3/1266 Platz 335-193 i 3,339,161 8/1967 Conner v 335-l93 BERNARD A. GILHEANY, Primary Examiner H. BROOME, Assistant Examiner 

